My top five tips on getting rid of knee pain are as follows:
1) Sort out your lower limb and pelvic alignment - it's unlikely that you will do this yourself because it is multi-faceted so go and see a physio who gives you standing exercises to sort this out (if your physio only gives you lying down exercises I would recommend a second opinion.)
2) Gradually load your knee with exercises using body weight and then additional weights starting statically if need be and then introducing movement and going up to fast movements if required for your sport/activity. Make sure this is done through the whole range of movement required.
3) Lose any extra pounds you are carrying. Boring but important.
4) Strengthen your hip and lower back/deep abdominal muscles.
5) Wear decent shoes - supportive running shoes or something similar.
For more information on how the knee works or common knee injuries like anterior knee pain - patello-femoral pain, patella tendinopathy (previously called tendinitis) or fat pat irritation, lateral knee pain - ITB friction syndrome or are worried about clicking/crunching/grinding knees please click on the links or have a rummage through the 'your injury' section of the Octopus Clinic website.
If you fell, had an accident or the pain came on suddenly, then you may have torn a ligament, cartilage or other structure like a meniscus or even suffered a fracture. In that case you need to get the knee assessed by a Physiotherapist or Osteopath ASAP. Even if you have not had a traumatic injury it is essential that you get pain and other symptoms assessed by a Physiotherapist or Osteopath, so that you do not do further damage.